solves the problem. But on more complicated cases,
Beam_collision_engraver

should handle this.

Or, at least for the moment, we should add "\remove
Beam_collision_engraver"

to the ossia staves doc (NR 1.6.2).
Regards,
Bertrand

Which version of 2.13 are you using?

For the record, Bertrand reported on .devel that he is using 13.59, so Bug
Squad would not be able to reproduce this, since it's not yet the released
version. It's also reported fixed, so if there is a problem in 13.60,
please re-post the report.